Quoted from Discogs (history of the Item - copy in my hand ---> 2 LP box)
This is actually an unmarked SQ Quadraphonic version, per this thread on QuadraphonicQuad.com . This is denoted by the "SQ" legend on the labels, and in the deadwax.
This also means it was a 2nd pressing, as the original pressing had separate Stereo and Quad issues; second pressings came after the separate Quad version was deleted from the catalog and Quad stampers were used for the subsequent pressings.